I just recently changed the plugs and wires in my 05 Grand Caravan and now I'm getting a misfire on cylinder #1. I pulled the plug back out of #1 and realized that it was broke. I had no choice at the time but to put one of the old ones back in. I was getting a code P 0301. I disconected the battery and connected it back on and the code went away but the problem didn't. It idles rough and shakes on start up and when I put it in gear. After a couple of minutes it seems to be fine but I don't want to take it too far in case something happens. It never did this before the plug change.
I put in Champion Double Platinum plugs. I checked the gaps and they seem to be fine. It is 3.8l V6 with about 208000 kms. It was fine before the plug change. I am at a loss. I'm not much of a Mechanic.
I don't think any of the plug had fallen into the cylinder but it is possible that some dirt has fallen in. It is at the back and I just reached over the engine so I couldn't see what I was doing. I will try your suggestion plus I will also try switching the old plug with one of the new ones. If the misfire moves then I know it's the plug. If not, then chances are that some dirt has fallen in.
I tried the old wire again with the same results. I took the new plug out of 3 and put it in 1. Took another old plug and put it in 3. New wires back on and all seems to be well. No more shaking. True test will be tomorrow as I drive a little better than 100kms to work one way. Wish me luck.